Bioreactor container and integrity check method for bioreactor containers

ABSTRACT

A bioreactor container comprising has an at least locally flexible wall and at least one container opening. The wall of the bioreactor container has a fluid-tight inner sheet, and an at least locally fluid-permeable or structured outer sheet. A method for testing the integrity of the bioreactor container also is provided.

BACKGROUND

1. Field of the Invention

The present description relates to a bioreactor container and to amethod for nondestructive testing of the integrity of bioreactorcontainers.

2. Description of the Related Art

In the pharmaceutical and biotechnology industries, flexible containers,for example bags, are used as bioreactor containers for processing orstorage. The bioreactor containers may become damaged before actual useby the production process, transport or handling. It is thereforerecommendable to carry out an integrity test of the bioreactor containerbefore actual use. An integrity test is also expedient after use of thebioreactor container, in order to ascertain whether the integrity of thebioreactor container was maintained throughout the entire processing.

The term “bioreactor container” in the context of the applicationequally includes bioreactors and containers having locally flexiblewalls, which are used for example to receive, mix, store and dispensesterile media.

Conventional test methods for testing the integrity of the bioreactorcontainer are the pressure drop method, flow measurement and trace gasanalysis with the use of a test gas. A common feature of all the testmethods is that a pressure difference is generated between the interiorof the bioreactor container and a test apparatus containing thebioreactor container, or the surroundings of the bioreactor container.To this end, after production, or before and/or after use, thebioreactor container to be tested is arranged in a test apparatus fortesting the integrity. This entails the risk that the bioreactorcontainer to be tested will become damaged during the handling necessaryfor this, so that a leak is formed in the per se leaktight bioreactorcontainer.

It is therefore an object of the invention to provide a bioreactorcontainer and a method for testing the integrity of bioreactorcontainers, which allow improved integrity testing of the bioreactorcontainer.

SUMMARY OF THE INVENTION

One aspect of the present invention relates to a bioreactor containercomprising:

-   -   an at least locally flexible wall and    -   at least one container opening,        wherein the wall of the bioreactor container has at least one        fluid-tight inner sheet, and        wherein the wall of the bioreactor container has an at least        locally fluid-permeable outer sheet.

Advantageously, the bioreactor container can be tested with respect toits integrity, or leaktightness, when the bioreactor container islocated in a bioreactor container compartment of a bioreactor apparatuswhich is employed for intended use of the bioreactor container. Furtherhandling of the bioreactor container, and therefore an additional riskof damage, are therefore advantageously avoided.

A bioreactor container comprises a fluid-tight wall, which is at leastlocally flexible. The term “bioreactor container” in the context of theinvention equally includes bioreactors and containers having locallyflexible walls, which are used for example to receive, mix, store anddispense sterile media. In particular, the bioreactor container has awall which is formed from a film or a composite or laminate of aplurality of films. In other words, the bioreactor container may beformed as a bag. The bioreactor container is of variable volume. Inother words, the internal volume of the bioreactor container can beincreased by filling and decreased by emptying. For filling andemptying, the bioreactor container has at least one container opening.The at least one container opening is preferably formed as a gland orconnector, so that fluid lines can be connected to the bioreactorcontainer in a straightforward way by means of the at least one gland.During intended use, the bioreactor container is filled with startingsubstances or reactants through the at least one container opening, andthe final substances or products are emptied through the at least onecontainer opening. The filling and emptying of the bioreactor containerpreferably take place through two different container openings, so thatthe bioreactor container expediently has at least two containeropenings. It is to be understood that each of the at least one containeropenings is sealable, or is closed, fluid-tightly, in particularsterilely.

The leaktightness of the wall in relation to a fluid is ensured by afluid-tight inner sheet of the wall. The inner sheet is in contact byone inner sheet side with the internal volume of the bioreactorcontainer. In other words, during intended use the reactants or productsof the biological, chemical or biochemical reaction, which is to becarried out or has been carried out in the bioreactor container, are incontact with the inner sheet. The inner sheet of the bioreactorcontainer therefore preferably consists of a material which isbiologically and chemically inert with respect to the reaction to becarried out, that is to say the inner sheet itself essentially does notreact with the reactants or products in the biological or chemicalsense. The inner sheet preferably consists of a polymer, for examplepolyethylene (PE) and/or polypropylene (PP). More preferably, at leastthe interior of the bioreactor container enclosed by the inner sheet issterilizable, for example by means of steam, gassing with ethyleneoxide, plasma treatment or gamma irradiation, so that the reaction canbe started under sterile conditions. More preferably, the containeropenings are formed as sterile connectors or are fluidically connectedto sterile connectors, for example through a tube. In the state readyfor use, in particular at least the interior of the bioreactor containeris sterile. More preferably, the entire bioreactor container is fullysterilized and sterilely packaged in the state ready for use.Preferably, the bioreactor container is intended for single use. Inother words, the bioreactor container is a disposable product.

The inner sheet is at least locally, and preferably fully, flexible. Itis to be understood that the inner sheet of the wall may be locallyrigid. Particularly in the region of the one container opening, theinner sheet of the wall may be essentially rigid, so that the at leastone container opening has a stable shape.

The wall of the bioreactor container comprises an at least locallyfluid-permeable outer sheet. This means that the outer sheet is at leastlocally fluid-permeable, or the wall only locally comprises an outersheet. In particular, the region of the wall which is flexibly formedhas an outer sheet. Accordingly, for example, a rigid region of the wallmay be formed merely as an inner sheet. As an alternative, the wall maybe rigidly formed but have an outer sheet, which may not befluid-permeable.

The outer sheet of the wall is fluid-permeable in the sense that a fluidwhich, contrary to intention, emerges from the interior of thebioreactor container through a leak of the inner sheet can also passthrough the outer sheet. In other words, the outer sheet does notfulfill an additional sealing function. Rather, the function of theouter sheet is to separate the inner sheet from objects outside thebioreactor container so that such an object essentially does not come indirect mechanical contact with the inner sheet but merely comes incontact with the outer sheet, so that the mechanical stress on the innersheet is also advantageously reduced. Furthermore, a leak in the innersheet cannot be externally sealed by means of the object, since theouter sheet is fluid-permeable. A fluid emerging from the bioreactorcontainer through the inner sheet would accordingly find a path throughthe fluid-permeable outer sheet to a position of the outer sheet whichdoes not come in contact with the object, and can enter the surroundingsthere. Such an object may, for example, be a bioreactor containercompartment of a bioreactor apparatus.

Bioreactor containers for carrying out a biological reaction maypreferably have an internal volume of from about 5 milliliters to about3000 liters, preferably about 2 liters, about 5 liters, about 10 liters,about 50 liters, about 100 liters, about 250 liters, about 500 liters orabout 1000 liters. Usually, during intended use, bioreactor containersare filled with an aqueous solution so that the content of thebioreactor container has a mass of from about 5 g to about 3000 kg.Since the walls of the bioreactor container cannot in general withstandthe internal pressure which is generated by the mass of the content ofthe bioreactor container, bioreactor containers are generally arrangedin the bioreactor container compartment of the bioreactor apparatus, andfastened therein. In this case, the wall of the bioreactor containerbears at least locally on the wall of the bioreactor containercompartment, so that the bioreactor container compartment supports thewall of the bioreactor container. The walls of such bioreactor containercompartments are usually formed from smooth stainless steel, in order tomake contamination more difficult and to facilitate cleaning.

If an integrity test is then carried out after the bioreactor containerhas been arranged in the bioreactor container compartment, the interiorof the bioreactor container being filled with a fluid in order togenerate a positive pressure relative to the surroundings, the wall ofthe bioreactor container compartment could cover a possibly existingleak in the wall of the bioreactor container. Yet since the outer sheetof the wall of the bioreactor container is fluid-permeable, it isadvantageously not possible for a smooth wall of the bioreactorcontainer compartment to seal the leak in the wall of the bioreactorcontainer by the wall of the bioreactor container being pressed againstthe wall of the bioreactor container compartment owing to the pressureprevailing inside the bioreactor container. This advantageously permitsan improved integrity test, by which leaks in the wall of the bioreactorcontainer can be determined with greater reliability, since it avoids aleak being inadvertently closed during the integrity test.

Furthermore, the integrity test of the bioreactor container canadvantageously be carried out “in situ” before and/or after theexperimental run, or the production process, that is to say when thebioreactor container is arranged in the bioreactor containercompartment, which advantageously avoids additional handling of thebioreactor container and therefore a risk of damaging the bioreactorcontainer by the additional handling.

The outer sheet is preferably porous, or comprises a porous material,the individual pore volumes expediently being connected to one anotherin such a way that the outer sheet is fluid-permeable. More preferably,the fluid-permeable outer sheet may have a direction-dependent, oranisotropic, fluid permeability. For example, the fluidic conductivityof the outer sheet in a direction parallel to the normal to the outersheet surface may be greater than in a direction perpendicular to thisnormal, that is to say parallel to the extent of the outer sheetsurface.

Preferably, the fluid-permeable outer sheet is connected releasably ornonreleasably to the fluid-impermeable inner sheet. The outer sheet maybe connected fully or locally to the inner sheet, for example byadhesive bonding, welding or lamination. As an alternative, the outersheet may also merely be drawn or pulled over the inner sheet. In otherwords, the outer sheet may be arranged releasably on the inner sheet orfirmly connected to the inner sheet, or fastened on the inner sheet. Theconnection between the outer sheet and the inner sheet may also takeplace merely along connecting lines, connecting edges or at connectingcorners. Accordingly, the outer sheet may be separated at least locallyfrom the inner sheet, in which case the intermediate space between theouter sheet and the inner sheet may for example be filled with air oranother gas.

Preferably, the fluid-permeable outer sheet comprises a woven textile, anonwoven textile and/or a foam material. Nonwovens, for example spunnonwovens of polypropylene, may be used as preferred materials for theouter sheet. One such nonwoven is for example Novatexx 2019 Viledon fromthe company Freudenberg Filtration Technologies KG, made ofpolypropylene with a weight of 17-100 g/m2 and an air permeability of1000-5000 l/m2 s at a pressure difference of 1 bar with a materialthickness of 0.25-0.75 mm. Another exemplary material is available underthe brand name Porex Porous Plastics XS XS49020-XS49100 from the companyPorex Technologies GmbH. The material consists of polypropylene andpolyethylene with a material thickness of from about 1.5 mm to about 5mm, preferably more than about 3 mm. The size of the pores lies in therange of from about 20 μm to about 175 μm, preferably less than about120 μm. The air permeability is from about 150 to about 300 l/cm2 minwith a 1.2 inch water column. It has proven advantageous to use apolymer material which contains thermally conductive additives, forexample boron nitrate, for the fluid-permeable outer sheet. In this way,temperature control of the bioreactor container can advantageously beimproved.

Preferably, the inner sheet may comprise a plurality of inner sheetlayers, which are connected to one another. For example, two or moreinner sheet layers may be connected to one another by lamination. Inthis case, at least one of the inner sheet layers is fluid-tight.Preferably, all the inner sheet layers are formed fluid-tightly. Atleast one—preferably each—of the inner sheet layers is formed as asterile barrier. In other words, microorganisms, bacteria, viruses,prions, etc. cannot penetrate the inner sheet, or the inner sheetlayer(s), so long as the sterile barrier or barriers is/are intact.

In the context of the application, the term “flexible” includes bothplastic and elastic deformability. The term “fluid” includes a gaseousphase, a liquid phase and also a mixture of liquid and gaseous phases ofa substance.

One aspect of the present invention relates to a bioreactor containercomprising:

-   -   an at least locally flexible wall and    -   at least one container opening,        wherein the wall of the bioreactor container has a fluid-tight        inner sheet, and        wherein the wall of the bioreactor container has an at least        locally structured outer sheet.

The bioreactor container corresponds in its properties essentially tothe bioreactor container described above, the fluid-permeable outersheet being replaced with a structured outer sheet, which may befluid-permeable or fluid-impermeable. For this reason, the commentsabove relating to the bioreactor container, in particular relating tothe wall, the container opening and the inner sheet, apply accordingly.

In the context of the application, a structured outer sheet means thatat least the outer surface of the outer sheet is not smooth but has astructure, or a relief. In particular, the structure may be formed byelevations and depressions which are produced by variation of thematerial thickness of the outer sheet. That is to say, the outer sheethas a greater material thickness in the region of elevations than in theregion of depressions. As an alternative, the material thickness of theouter sheet may be essentially constant, the structure being molded intothe material. In this case, in particular, the flexibly formed region ofthe wall is provided with a structured outer sheet. Preferably, however,rigid regions of the wall may also have a structured outer sheet, or astructured outer surface. The outer surface refers to the face of thewall which lies away from, or opposite, the side of the wall facing theinterior of the bioreactor container. Typically, the bioreactorcontainer is gripped and handled on the outer surface.

In contrast to the alternatives described above, the outer sheet of thewall may be fluid-impermeable, so that the outer sheet canadvantageously fulfill an additional sealing function. Nevertheless, thestructured outer sheet leads to an equivalent technical effect as afluid-permeable outer sheet, in the sense that a leak in the inner sheetcannot be externally sealed by means of an object. Owing to thestructure of the outer sheet, an object cannot in general joinfluid-tightly with the outer sheet in such a way that a fluid emergingfrom the bioreactor container through the inner sheet would not reachthe surroundings. In particular, such sealing cannot take place by meansof a bioreactor container compartment of a bioreactor apparatus.Accordingly, an integrity test can be carried out by applying a positivepressure to the bioreactor container, a pressure drop or a fluid flowdue to the leak being detectable and making it possible to deduce thatthere is a leak.

As already described above, the bioreactor container may be arranged inorder to carry out a biological reaction in the bioreactor containercompartment of the bioreactor apparatus, the wall of the bioreactorcontainer bearing at least locally on the essentially smooth wall of thebioreactor container compartment.

When an integrity test of the bioreactor container is carried out in thebioreactor container compartment, the structured outer sheet is pressedagainst the wall of the bioreactor container compartment. The effect ofthe structure of the outer sheet is that, owing to the arrangement ofthe outer sheet on the bioreactor container compartment, channelsconveying fluid are formed between the two. In this way, a fluidpenetrating the outer sheet through a leak can be delivered into thesurroundings through the channels conveying fluid, so that the leak inthe wall of the bioreactor container cannot be sealed by the wall of thebioreactor container compartment. As already described above, thisadvantageously permits an improved integrity test by which leaks in thewall of the bioreactor container can be determined with greaterreliability, since it avoids a leak being inadvertently closed duringthe integrity test, and furthermore the integrity test of the bioreactorcontainer can advantageously be carried out “in situ” before and/orafter the experimental run, or the production process.

Preferably, the structured outer surface has depressions which are atleast about 100 μm deep. In this case, two neighboring depressionsdefine, or form, an elevation. Likewise, at least two neighboringelevations define, or form, a depression. More preferably, thedepressions have at least a depth of more than about 150 μm, morepreferably more than about 250 μm, and in particular more than about 500μm, relative to the neighboring elevations. This ensures release of thefluid emerging from a leak into the surroundings.

Preferably, the structured outer side has elevations which are at most200 μm wide. More preferably, the elevations have a width of less thanabout 150 μm, more preferably less than about 100 μm, and in particularless than about 50 μm. This prevents the possibility that an elevationcan be positioned with an accurate fit on a leak and that the leak canthereby be sealed by a single elevation. The expected diameter of a leakis from about 5 μm to about 1000 μm.

Preferably, the elevations and/or depressions of the structured outerside are oriented along a preferential direction V. In particular, theelevations and/or depressions extend essentially along a longitudinaldirection L, neighboring elevations and/or depressions being orientedparallel to one another. The preferential direction V in this casecorresponds to the longitudinal direction L along which the elevationsor depressions extend. In other words, the elevations and depressionsmay in particular form a groove structure or a rhombic structure on theouter sheet, or the outer surface.

Preferably, the structured outer sheet is connected releasably ornonreleasably to the fluid-impermeable inner sheet. The structured outersheet may be connected fully or locally to the inner sheet, for exampleby adhesive bonding, welding or lamination. As an alternative, thestructured outer sheet may also merely be drawn or pulled over the innersheet. In other words, the structured outer sheet may be arrangedreleasably on the inner sheet or firmly connected to the inner sheet, orfastened on the inner sheet. The connection between the structured outersheet and the inner sheet may also take place merely along connectinglines, connecting edges or at connecting corners. Accordingly, thestructured outer sheet may be separated at least locally from the innersheet, in which case the intermediate space between the structured outersheet and the inner sheet may for example be filled with air or anothergas. More preferably, the structured outer sheet is formed as a sterilebarrier.

Preferably, the two alternative bioreactor containers described aboveare formed in such a way that the at least one container opening of thebioreactor container is enclosed in a first state by the outer sheet,the at least one container opening being freely accessible in a secondstate, and the bioreactor container being convertible from the firststate to the second state by local removal of the outer sheet. In thiscase, the outer sheet may be fluid-permeable and/or structured.

Advantageously, the outer sheet may also be used as protection and/orsterile closure, or packaging, of the at least one container opening. Inparticular, in the first state the outer sheet may form a closedencapsulation around the other elements of the bioreactor container,which preferably packages these elements sterilely. During handling, thebioreactor container may be arranged in the bioreactor containercompartment before subsequently being converted into the second state,for example by tearing the outer sheet, which can then preferably bepulled over a region of the bioreactor container compartment.

Preferably, the outer sheet may be formed from polyethylene, a compositeor laminate of polyethylene and polypropylene, or a material which isknown by the brand name Tyvek®. In particular, Tyvek® is permeable tosteam so that sterilization of the bioreactor container can be carriedout by means of steam, this material constituting a sterile barrier.

The invention also relates to a method for testing the integrity of abioreactor container, having the steps:

-   -   providing a bioreactor container according to the invention;    -   providing a bioreactor apparatus having a bioreactor container        compartment;    -   arranging the bioreactor container at least partially in the        bioreactor container compartment;    -   connecting the at least one container opening of the bioreactor        container to a fluid source;    -   filling the bioreactor container with a fluid from the fluid        source in order to generate a predetermined positive pressure P₁        in the bioreactor container at a first time T₁, the outer sheet        of the bioreactor container bearing at least locally on an inner        wall of the bioreactor container compartment;    -   determining whether the bioreactor container is sufficiently        leaktight.

In this case, the determination may in particular be carried out withthe aid of a pressure difference (P2−P1) between a positive pressure P2at a subsequent time T2 and the determined positive pressure at time T1.As an alternative or in addition, the determination may be carried outwith the aid of a fluid quantity M which has been delivered to thebioreactor container after the time T₁, in order to keep the positivepressure P₁ constant. Furthermore, as an alternative or in addition, thedetermination may be carried out with the aid of detection, outside thebioreactor container, of fluid particles which have been delivered tothe bioreactor container. Advantageously, the accuracy of thedetermination or ascertainment, and decision whether the bioreactorcontainer is leaktight, can be increased when two or three of thequantities described above are detected. The probability that theleaktightness of the bioreactor container will be incorrectly classifiedor determined is thereby advantageously reduced.

An integrity test provides information about the integrity, orleaktightness, of the bioreactor container, in particular as to whetherfluids can emerge from a leak or enter. In particular, the integrity isviolated and the bioreactor container is unusable when microorganismscan enter the interior of the bioreactor container through a leak, sothat the reaction inside the bioreactor container is compromised and theresulting products are unusable. Advantageously, the bioreactorcontainer may bear on the inner wall of the bioreactor containercompartment, the result of the integrity test not being influenced sincesealing of existing leaks by the inner wall is avoided. In particular,an integrity test can be carried out when the bioreactor container isalready contained in the bioreactor container compartment of thebioreactor apparatus with which the actual reaction is subsequentlycarried out.

The determination of whether the container is sufficiently leaktight mayin particular be carried out by means of the pressure drop method, bymeasuring the fluid delivery rate at constant pressure, and by means ofa test gas as the fluid. The test gas is expediently a gas which doesnot occur, or occurs only in traces, in the atmosphere, and cantherefore be detected easily at the leak sites by means of a gasdetector. The positive pressure P1 of the fluid inside the bioreactorcontainer relative to the atmospheric pressure is between about 20 mbarand about 500 mbar, preferably between about 50 mbar and about 300 mbar.

Preferably, the method comprises the subsequent steps:

-   -   filling the bioreactor container with reactants;    -   carrying out a chemical or biochemical reaction in the        bioreactor container;    -   releasing the content from the bioreactor container.

Advantageously, the integrity test may be integrated into the productionmethod, since the bioreactor container can be filled with the reactants,or starting substances of the reaction, directly following the integritytest. In order to remove the rest of the fluid used for the integritytest from the bioreactor container, the starting substances mayexpediently be delivered through a container opening located underneathon the bioreactor container, while the fluid is vented through acontainer opening located above, in particular through a sterile filter.Particularly in the case of starting substances containing protein,foaming is advantageously avoided.

Preferably, the determination of whether the bioreactor container issufficiently leaktight is performed before and/or after the biochemicalreaction is carried out in the bioreactor container. Preferably, themethod comprises the steps following release:

-   -   connecting the at least one container opening of the bioreactor        container to a fluid source;    -   filling the bioreactor container with a fluid from the fluid        source in order to generate a predetermined positive pressure P₁        in the bioreactor container at a first time T₁, the outer sheet        of the bioreactor container bearing at least locally on an inner        wall of the bioreactor container compartment;    -   determining whether the container is sufficiently leaktight.

The determination is preferably carried out with the aid of a pressuredifference (P2−P1) between a positive pressure P2 at a subsequent timeT2 and the determined positive pressure at time T1. As an alternative,the determination is carried out with the aid of a fluid quantity Mwhich has been delivered to the bioreactor container after the time T₁,in order to keep the positive pressure P₁ constant. Furthermore, as analternative, the determination may be carried out with the aid ofdetection of fluid particles outside the bioreactor container, the fluidparticles (for example a test gas) having been delivered to thebioreactor container.

In other words, after the end of the reaction a final integrity test mayadvantageously be carried out in order to check whether the bioreactorcontainer has retained its integrity throughout the entire time of thereaction.

Preferred embodiments of the present invention will be explained by wayof example below with the aid of the appended drawings. Individualfeatures of the preferred embodiments presented may be combined to formother preferred embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a perspective view of one preferred embodiment of abioreactor container;

FIG. 2 shows a perspective view of another preferred embodiment of abioreactor container;

FIG. 3 shows a perspective view of another preferred embodiment of abioreactor container;

FIG. 4 shows a section through one embodiment of a wall having afluid-tight inner sheet and a fluid-permeable outer sheet;

FIG. 5a shows a section through one embodiment of a structured outersheet;

FIG. 5b shows a plan view of the structured outer sheet;

FIG. 6a shows a section through another embodiment of a structured outersheet;

FIG. 6b shows a plan view of the structured outer sheet;

FIG. 7a shows a section through another embodiment of a structured outersheet;

FIG. 7b shows a plan view of the structured outer sheet;

FIG. 8 shows a schematic view of one preferred embodiment of abioreactor container;

FIG. 9 shows a schematic view of an apparatus for testing the integrityof the bioreactor container;

FIG. 10 shows one preferred embodiment of a bioreactor container.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 shows one preferred embodiment of a bioreactor container 1 in aperspective view. In this regard, it should be noted that the term“bioreactor container” in the context of the invention includes equallybioreactors and containers having locally flexible walls, which are usedfor example to receive, mix, store and dispense sterile media. Thebioreactor container 1 comprises a wall 3 which has a fluid-impermeable,or fluid-tight, inner sheet 5 and a fluid-permeable outer sheet 7. Theinner sheet 5 is formed from a nonporous flexible material, so that avariable internal volume is enclosed by the inner sheet. The internalvolume of the bioreactor container 1 can be fluidically connected to thesurroundings or to further elements, for example fluid lines, throughthe four container openings 9 a, 9 b, 9 c, 9 d. It is to be understoodthat the flexible inner sheet 5 may be formed more stiffly, or rigidly,in the region of the container openings, so that the container openings9 a, 9 b, 9 c, 9 d have a stable shape and glands and connectorsoptionally connected thereto remain leaktight. The bioreactor container1 can be filled and emptied through the container openings 9 a, 9 b, 9c, 9 d. The outer sheet 7 is formed from a fluid-permeable porousmaterial, which is arranged essentially separated from the inner sheet5. The inner sheet 5 and the outer sheet 7 are in this case connected toone another pointwise in the region of the corners.

The bioreactor container 1 shown in FIG. 1 has a box-like or cuboidshape. The inner sheet 5 and the outer sheet 7 are therefore connectedto one another at the eight corners of the box or cube. This connectionmay, for example, be carried out by welding or adhesive bonding, inparticular on tabs 11 which protrude from the inner sheet 5 and/or theouter sheet 7. As an alternative or in addition, the inner sheet 5 andthe outer sheet 7 may be connected, welded or adhesively bonded to oneanother in the region of the container openings 9 a, 9 b, 9 c, 9 d.

It is to be understood that the bioreactor container 1 may also have atetrahedral, cylindrical, spherical, prismatic or other desired shape.The number of connecting regions at which the inner sheet 5 and theouter sheet 7 are then connected to one another can then be variedaccordingly.

Irrespective of the external shape, the outer sheet 7 may be configuredrigidly or flexibly. Advantageously, a rigid outer sheet 7 makes itpossible that the bioreactor container always assumes a defined volumeand that it can be handled by means of the rigid outer sheet 7 withoutexerting a pressure on the inner sheet during handling. As analternative, the outer sheet 7 may be formed flexibly, so that thebioreactor container 1 can be easily folded and stored compactly. In theregion of the container openings 9 a, 9 b, 9 c, 9 d, the outer sheet 7preferably has access openings 13 a, 13 b, 13 c, 13 d through which thecontainer openings 9 a, 9 b, 9 c, 9 d are accessible, or through whichconnectors or lines coming from the container openings 9 a, 9 b, 9 c, 9d can protrude.

FIG. 2 shows another preferred embodiment of a bioreactor container 1 ina perspective view. The structure of the bioreactor container 1corresponds essentially to the structure of the bioreactor container 1shown in FIG. 1, elements in FIG. 2 identical to FIG. 1 being denoted bythe same references.

The bioreactor container 1 shown in FIG. 2 has an inner sheet 5 and anouter sheet 7, which are connected to one another along weld seams 13.Expediently, the inner sheet 5 and the outer sheet 7 are connected toone another on the edges of the wall 3, for example by welding oradhesive bonding. The linear connection of the inner sheet 5 to theouter sheet 7 advantageously leads to a more stable connection, whichincreases the torsional stiffness of the bioreactor container 1.

FIG. 3 shows another preferred embodiment of a bioreactor container 1 ina perspective view. The structure of the bioreactor container 1corresponds essentially to the structure of the bioreactor containers 1shown in FIGS. 1 and 2, so that identical elements in FIG. 3 are denotedby the same references.

The bioreactor container 1 shown in FIG. 3 has an inner sheet 5 and anouter sheet 7, the outer sheet 7 only locally enclosing the inner sheet5, or only locally being arranged on the inner sheet 5. In particular,the bioreactor container 1 does not have an outer sheet 7 on the side onwhich the container openings 9 a, 9 b are formed. This is not necessaryin particular when the bioreactor container 1 does not come inmechanical contact with a bioreactor container compartment in thisregion during intended use. The inner sheet 5 and the outer sheet 7 maybear fully on one another, or be fully connected to one another. Forexample, the inner sheet 5 and the outer sheet 7 may be adhesivelybonded or laminated to one another. It is to be understood that theouter sheet 7 may also merely be pulled releasably over the inner sheet5. In particular, the outer sheet 7 may be delivered as one or moredistinct elements separately from the rest of the bioreactor container1, so that the outer sheet 7 is not arranged on the inner sheet 5 untilintended use of the container. Expediently, the outer sheet 7 and therest of the bioreactor container are delivered as a set inside apackaging unit.

FIG. 4 shows a section through an embodiment of a wall 3 having afluid-tight inner sheet 5 and a fluid-permeable outer sheet 7. In thispreferred embodiment, the outer sheet consists of a porous layer of anonwoven material or a foam material having continuous pores.Advantageously, the outer sheet 7 is mechanically durable and cantherefore protect the underlying inner sheet 5 against mechanicalinfluences.

In the preferred embodiment shown, the inner sheet 5 comprises aplurality of inner sheet layers 5 a, 5 b, 5 c, 5 d, which are connectedto one another. For example, the inner sheet layers 5 a, 5 b, 5 c, 5 dmay be connected to one another by lamination or adhesive bonding.

A contact inner sheet layer 5 a consists of a material which isbiologically or chemically inert with respect to the reactions to becarried out inside the bioreactor container, that is to say the innersheet itself essentially does not react biologically or chemically.Preferably, the contact inner sheet layer 5 a consists of a polymer, forexample polyethylene (PE) and/or polypropylene (PP). In order to formthe wall 3 fluid-tightly in the sense of gastightly, the inner sheet mayhave a gastight inner sheet layer 5 b, or a gas barrier 5 b. Themechanical stability of the wall may be produced by one or moremechanically supporting inner sheet layers 5 c, 5 d. These mechanicallysupporting inner sheet layers 5 c, 5 d may be formed fluid-tightly, butmay also be fluid-permeable or gas-permeable if the contact inner sheetlayer 5 a and the gas barrier 5 b ensure sufficient fluid-tightness.

As an alternative to the fluid-permeable or porous outer sheet 7, astructured outer sheet 7 may also be provided in the wall 3.

FIG. 5a shows a section through, and FIG. 5b shows a plan view of, oneembodiment of a structured outer sheet 7. In this embodiment, the outersheet 7 has depressions 7 a and elevations 7 b, which extend parallel toone another along a longitudinal direction L. In other words, theelevations 7 b and depressions 7 a form a groove structure on the outersheet 7, or the outer surface. The elevations 7 b and depressions 7 aare formed by variation of the material thickness of the outer sheet 7.Preferably, the structured outer side comprises elevations which have awidth b of at most about 200 μm, preferably about 50 μm, and a height hof at most about 200 μm, preferably about 50 μm.

FIG. 6a shows a section through, and FIG. 6b shows a plan view of, oneembodiment of a structured outer sheet 7. In this embodiment, the outersheet 7 has hemispherical elevations 7 c, or pimples 7 c. The pimples 7c are preferably arranged regularly on the outer sheet 7. The elevationsor pimples 7 c preferably have a height h of at most about 200 μm. Thepoint bearing should be less than 5 μm, preferably less than 2.5 μm, butat any rate at most half the diameter of the hole size to be detected.

FIG. 7a shows a section through, and FIG. 7b shows a plan view of, oneembodiment of a structured outer sheet 7. In this embodiment, the outersheet 7 has depressions 7 d and elevations 7 e which form a rhombicstructure on the outer sheet 7, or the outer surface. The elevations 7 eand depressions 7 d are formed by variation of the material thickness ofthe outer sheet 7, the elevations having a width b of at most about 5μm, preferably about 2.5 μm, and a height h of at least about 100 μm.

It is to be understood that the elevations and depressions of the outersheet 7 need not form a regular or periodic pattern, but may form anunordered, irregular structure.

FIG. 8 shows a schematic view of a preferred embodiment of a bioreactorcontainer 1. FIG. 8 shows the bioreactor container 1 in a first state,the container openings 9 a, 9 b, 9 c in the inner sheet 5 of thebioreactor container 1 being enclosed by the outer sheet 7. In otherwords, in the first state the outer sheet 7 forms outer packaging of thebioreactor container 1, which encloses, in particular sterilelyencloses, the bioreactor container and in particular the containeropenings 9 a, 9 b, 9 c and optionally components 17 connected to thecontainer openings 9 a, 9 b, 9 c, for example fluid glands, connectors,sterile connectors or sterile filters. Advantageously, the outer sheet 7is thus used as protection and/or sterile closure or packaging of thebioreactor container 1, or its container openings 9 a, 9 b, 9 c. Thesterility state inside the outer sheet 7 of the bioreactor container 1,and optionally the sterility state of the components 17 enclosed by theouter sheet 7, may be documented by means of a sterility indicator 19.For example, the sterility indicator 19 may indicate, for example bycoloration, whether the bioreactor container 1 has received a sufficientradiation dose during sterilization by means of gamma radiation.

For example by tearing the outer sheet 7 at a separation boundary 21,the bioreactor container can be converted into a second state, in whichthe container opening 9 a, 9 b, 9 c, or the components 17 attached orconnected thereto, are freely accessible. The outer sheet 7 may in thiscase be separated in such a way that the outer sheet 7 remains at leastlocally connected to the inner sheet 5. A part of the outer sheet eithermay be removed or is separated in such a way that this part can befolded or pulled back in order to obtain access to the containeropenings 9 a, 9 b, 9 c, or the components 17 connected thereto.

FIG. 9 shows a schematic view of an arrangement 23 for testing theintegrity of the bioreactor container 1. For the test, the bioreactorcontainer 1 is arranged in a bioreactor container compartment 25 of abioreactor apparatus. The at least one container opening 9 a of thebioreactor container 1 is fluidically connected to a fluid source 27,for example by means of a sterile filter 29 in order to keep theinterior of the bioreactor container 1 sterile. The fluid source may bepart of a test apparatus 31, for example Sartocheck® 4plus fromSartorius Stedim Biotech GmbH, or it may be an external fluid source 27.

The bioreactor container 1 is filled with a fluid from the fluid source27 at a time T1 with a predetermined positive pressure P1 of from about50 mbar to about 100 mbar, the outer sheet 7 of the bioreactor container1 bearing at least locally on an inner wall of the bioreactor containercompartment 25.

The pressure difference P2−P1 between a positive pressure P2 at asubsequent time T2 and the determined positive pressure at time T1 maybe detected by means of an internal pressure sensor 33 of the testapparatus 31. As an alternative or in addition, the pressure inside thebioreactor container 1 may be detected by means of an external pressuresensor 35. The external pressure sensor 35 is preferably connected tothe test apparatus 31 via a signal line 37. With the aid of the pressuredifference P2−P1, it is possible to determine whether the bioreactorcontainer 1 is leaktight, or has integrity. To this end, the pressuredifference must be less than a predetermined amount, in the ideal caseequal to zero. Advantageously, the bioreactor container 1 may bear onthe inner wall of the bioreactor container compartment 25 during thetest, the result of the integrity test not being influenced since thesealing of leaks which exist by the inner wall is avoided owing to theconfiguration of the outer sheet 7.

FIG. 10 shows a preferred embodiment of a bioreactor container 1, whichis arranged in a bioreactor compartment 25. The bioreactor container 1comprises a wall 3, which has a fluid-impermeable inner sheet 5 and afluid-permeable outer sheet 7. The wall 3 may preferably consist of afilm, or a laminate of a plurality of films. In other words, the wall 3may be formed essentially as a flexible bag, which can vary in shape.The inner sheet 5 is formed from a nonporous flexible material, so thata variable internal volume is enclosed by the inner sheet. The internalvolume of the bioreactor container 1 can be connected fluidically to thesurroundings or to further elements, for example fluid lines, by meansof a container opening 9 a and a sterile filter 29. The outer sheet 7 isformed from a fluid-permeable porous material or from asurface-structured material, which is arranged essentially separatedfrom the inner sheet 5 and is connected releasably to the inner sheet 5by means of a fastening device 39. To this end, the outer sheet 7 may befixed on the fastening device 39 by means of fixing elements 41. Afterthe test, the fixing elements, for example clamps or screws, may bereleased and the outer sheet 7 may be removed.

The invention claimed is:
 1. A single use, disposable bioreactorcontainer (1) comprising: an at least locally flexible wall (3); atleast one container opening (9 a, 9 b, 9 c, 9 d), wherein the wall (3)of the bioreactor container (1) has a fluid-tight inner sheet (5),wherein the wall (3) of the bioreactor container (1) has an at leastlocally fluid-permeable outer sheet (7), and wherein the fluid-permeableouter sheet (7) is connected locally to the fluid-tight inner sheet (5)and also is separated locally from the fluid-tight inner sheet (5) sothat a fluid emerging from the bioreactor container (1) through a leakin the fluid-tight inner sheet (5) finds a path through thefluid-permeable outer sheet (7) to surroundings of the bioreactorcontainer (1).
 2. The bioreactor container (1) of claim 1, wherein thefluid-permeable outer sheet (7) comprises at least one of a woventextile, a nonwoven textile and a foam material.
 3. The bioreactorcontainer (1) of claim 1, wherein the fluid-permeable outer sheet (7)has a direction-dependent fluid permeability.
 4. A method for testingthe integrity of a bioreactor container (1), having the steps: providingthe bioreactor container (1) of claim 1; providing a bioreactorapparatus having a bioreactor container compartment (25); arranging thebioreactor container (1) at least partially in the bioreactor containercompartment (25); connecting the at least one container opening (9 a, 9b, 9 c, 9 d) of the bioreactor container to a fluid source (27); fillingthe bioreactor container (1) with a fluid from the fluid source (27) inorder to generate a predetermined positive pressure P₁ in the bioreactorcontainer (1) at a first time T₁, the outer sheet (7) of the bioreactorcontainer (1) bearing at least locally on an inner wall of thebioreactor container compartment (25); and determining whether thebioreactor container (1) is sufficiently leaktight.